osd: fix _activate_committed replica->primary message

osd: fix _activate_committed replica->primary message

Normally we take a fresh map reference in PG::lock().  However,
_activate_committed needs to make sure the map hasn't changed significantly
before acting.  In the case of #2068, the OSD map has moved forward and
the mapping has changed, but the PG hasn't processed that yet, and thus
mis-tags the MOSDPGInfo message.

Tag the message with the e epoch, and also pass down the primary's address
to send the message to the right location.

Fixes: #2068
Signed-off-by: Sage Weil <sage@newdream.net>